The oxidation effect on the cracking behavior of a co-based alloy under thermal shocks

Abstract Oxidation and cracking behavior during thermal-shock experiments of a new Co-based alloy were analyzed in the present work. Comparing to the static conditions, the oxidation behavior during thermal shocks is stress-assisted and crack-accelerated. Cracks during the thermal shocks were initiated from the sample surfaces and their growth is driven by various stresses, including those induced by volume change, mismatch of coefficient of thermal expansion (CTE), and temperature gradient between the matrix and the internal oxides. It is found that the crack propagation correlates to these stresses in the classic Paris’ law.